This study evaluates the ability of a high resolution (2-km horizontal resolution) Weather Research and Forecast (WRF) model driven with North American Mesoscale (NAM) output to simulate cloud liquid water (LW) over the Uinta Mountains of Utah. Radiometer observations of LW (a critical ingredient for effective cloud seeding), are compared with modeled cloud conditions to better understand the ability of an operational WRF configuration to provide insight into impending cloud seeding conditions. The LW was measured on the southern and northern slopes of the Uinta range during the winters of 2019 and 2022, respectively. The WRF model’s performance in forecasting LW was assessed by comparing it with the observed radiometer data. Results indicate that the model accurately predicted LW during major storms but exhibited discrepancies in magnitude, overestimating values on the southern slope and underestimating them on the northern slope. Statistical analysis revealed a bias score of 0.83 for 2019 and 1.06 for 2022, with a probability of detection of 0.74 and 0.70, respectively. This study demonstrates the value of the WRF model for supporting cloud-seeding operations while emphasizing the need for additional radiometer measurements to evaluate LW forecasts under very limited data availability. Because Utah’s complex terrain and varying mountain orientations create strong spatial variability in LW, expanded observations are crucial for validating model output and improving forecasts through better selection of cloud-microphysics and boundary-layer schemes. While the findings provide useful guidance for optimizing precipitation-enhancement strategies in Utah’s mountainous regions, WRF performance must be further assessed using longer-term LW datasets, as current forecasts show both positive and negative biases across the Uinta Range.
The effectiveness of cloud seeding for hail suppression is evaluated as conducted by the North Dakota Cloud Modification Project. A total of 88 Western North Dakota convective storm cases from 2016-2018 that include both seeded and unseeded storms are analyzed using a radar-based hail size retrieval algorithm. The algorithm determined hail sizes are compared to forecasted hail sizes derived from proximity sounding analysis from the Weather Research and Forecasting (WRF) model. Hail was placed into one of three bins: no hail, hail less than 2 inches in diameter, and hail greater than 2 inches in diameter. Model analysis includes two hail-centric indices, five severe weather indices, and the HAILCAST model. Results show strong agreement between forecasted and observed hail sizes in unseeded cases with 56 percent of cases matching hail size bins for both the forecast and radar-derived observation. In contrast, seeded storms showed less than 50 percent of cases had matching hail sizes. Rather, seeded cases consistently produced radar derived hail sizes smaller than forecasted hail sizes in 20.8 percent more cases than the unseeded category, indicating a hail suppression effect. The hail suppression is statistically significant at the 90 percent confidence level, with a p-value of 0.079. These findings support the potential of cloud seeding to mitigate hail damage and enhance agricultural resilience in Western North Dakota.
The Journal of Weather Modification (JWM) Volume 57 includes 2 science papers, and the President’s and Editor’s messages. We continue to work toward increased paper submissions as our transition to the new platform nears completion. We are also working toward a refreshed vision for the journal that accommodates emerging communication platforms and outreach streams. This evolution is especially important as we face an aging membership, a transition toward shorter contributions, and a growing global need for potable water, water security, and sustainability. The Journal of Weather Modification is an integral part of the WMA. It exists to document and facilitate interaction among operational, developmental, academic/research, and stakeholder communities within and beyond our organization. Proceeds from the JWM support WMA activities and help offset annual meeting costs. Each scientific article and technical note published in JWM receives 2 reviews and a unique DOI, ensuring global visibility and accessibility. “Short” contributions, such as technical notes based on WMA meeting presentations or operational project reports adapted to the JWM format, are just as important as full scientific articles. We also welcome contributions emerging from newer communication and outreach platforms. The process for assigning DOIs to some of these newer formats is still being finalized, but we are committed to making it work. Our current publishing platform does have a streaming capability. If you are considering a paper or topic-relevant submission, please contact the JWM Editor or any member of the Editorial Board to discuss its suitability. You may also visit our updated guidelines and submission page: https://journalofweathermodification.scholasticahq.com/for-authors. Click on submit the paper ‘wigit’. Once done a popup menu appears and includes a choice between submitting a revised manuscript or a new submission. Submissions (including scientific articles, technical notes/short contributions, President’s Messages, In Memoriam pieces, and outreach/communication topics) are accepted year-round through the journal’s website. You may need to create an account on our new journal host. We now use an improved review and publication system hosted by Scholastica, which is fully active on the association’s journal webpage. Tom Dr. Thomas P. DeFelice, WMA-CO/CM WMA JWM Editor, 2025-2026
Global warming and population growth are the largest contributing factors to the need to create more water. For a proposed cloud seeding project it is important to know whether or not it is economically justifiable and, if implemented, continues to be economically justified. This article discusses factors that impact preparing an economic analysis of existing and proposed cloud seeding projects.
• Parts of this paper were presented at the European Geophysical Union 2023 conference and the WMA 2023 annual meeting.
Research operations, using electrostatically charged water droplets as a seeding agent, were conducted in convective clouds over West Texas as an exploratory experiment in 2017. Research continued later in its confirmatory phase through 2022. The initial research flights were conducted using an Air Tractor 402B provided by the USDA, and later both a Piper Comanche and 502B were equipped to extend those operations. For the assessments of possible impacts, radar data and TITAN software were used, following the same protocols established for the evaluations of long-running operational cloud-seeding programs in Texas. A total of 18 small and isolated seeded clouds were compared with similar control (unseeded) cases provided by the TITAN software. Such a comparison indicated significant increases in lifetime, area, precipitation flux, and precipitation mass among other variables of interest, and the average increases appeared to be larger than those obtained with glaciogenic (silver iodide) flares used in the legacy rain-enhancement projects in Texas (1996-2023). In this paper, we summarize the approach taken in the research and results from the analysis of data, both of which led the U. S. Department of Agriculture to request a U. S. patent which has since been issued.
These comments are my opinion based on my academic, professional and non-professional experiences. They do not necessarily reflect those of any person I know or have known, nor current or former employers, organizations or other entities.
Abstract. A set of existing hydrologic models of the headwater and agricultural areas of the Walker River basin are used to estimate the effects of cloud seeding activities by Desert Research Institute on the amount of water delivered to the agricultural areas in the lower part of the basin over the water years 2004 through 2013. A monthly water balance model is used to simulate the accumulation and melt of the snowpack and the associated runoff in the headwater areas. A river basin management model is used to simulate the spatial and temporal complexity of the movement and use of surface and groundwater below the mountain front in the streams, reservoirs, irrigation ditches, and crop areas which are completely driven by water right priorities and water supply. In the two case studies presented, the effects of cloud seeding on two different target areas were identified and compared in terms of: (1) changes to the amount of surface water delivered to the crop areas for irrigation purposes; (2) changes in the amount of supplemental groundwater pumping; and (3) changes in crop shortage for each year over the study period. Estimates of crop irrigation water requirements and crop value per acre were used to estimate the financial benefits of the cloud seeding activities under a range of seeding efficiency estimates for each case. The results indicate that, over the study period, the benefits to seeding the target areas in the first case, characterized by relatively large long-term annual precipitation, are significantly greater than seeding the target area in the second case, characterized by less annual precipitation. The results from both studies provide useful information for planning and operational decisions related to cloud seeding in the Walker River basin.
North American Weather Consultants, Inc. (NAWC) has conducted operational winter cloud seeding programs in the mountainous areas of Central and Southern Utah since 1974. Beginning in 1988, seeding has also been conducted in three additional mountainous target areas within the State. The goal of these programs has been to enhance winter snowpack accumulation in the target areas, which now include most of the mountainous areas of the State. Studies have demonstrated that a large majority of the annual runoff in Utah streams and rivers is derived from melting snowpack, which explains the focus on wintertime seeding (within the November – April period). Augmented water supplies are typically used for irrigated agriculture or municipal water supplies. Programs are typically funded at the county level with cost sharing grants from the Utah Division of Water Resources (UDWR) and the three Lower Colorado River Basin States of Arizona, California, and Nevada, since 2007. An earlier WMA paper (Griffith et al. 2009) provided a summary of seeding operations for the water years of 1974 through 2007 for the four target areas. This paper is focused on the Central and Southern Utah program which is both the largest target area and the longest running program in the state. It covers all but three water years from 1974 through 2021 and is one of the three or four longest operational winter cloud seeding programs that have been conducted in the United States. The target area encompasses several mountain ranges in Central and Southern Utah. NAWC has defined the target area boundaries as those locations that are above 7,000 feet MSL. This is a large area of approximately10,000 square miles. Cloud seeding is accomplished using networks of ground-based, manually operated silver iodide nuclei generators located in valley or foothill locations upwind of the intended target mountain barriers. As such, these programs are classified as orographic winter cloud seeding programs. Orographic winter cloud seeding programs are typically categorized as those with the highest level of scientific support based upon capability statements of such organizations as the American Meteorological Society and the Weather Modification Association. NAWC historical target/control evaluations of this program indicate an average increase in December-March target area precipitation of 12% or an average increase in precipitation of 1.3”. These results were significant at the 0.06 level from a one-tailed Student’s t-test. The UDWR has conducted periodic studies to estimate the increases in annual streamflow resulting from the estimated increases in April 1st snow water content produced by this seeding program. The most recent study (UDWR 2018) indicated an estimated average annual streamflow increase of about 84,000 acre-feet for the Central and Southern Utah target area. Factoring in the cost of conducting this program resulted in an estimate of the average cost of the augmented runoff to be $2.02 per acre-foot.
Stakeholder management is instrumental in the success of a project and thus in the present study, different dimensions of stakeholder management were critically evaluated in the context of the rainfall enhancement project in Oman. The rainfall enhancement project, using the ionization technique, is among the major national projects recently undertaken by the Omani government to confront the country’s scarcity of water resources. Oman showed an interest in artificial rainfall in 2013, setting up an ambitious project that includes 12 ionization stations. The government decided to implement the Australian experience in artificial rainfall. This method is used by experts in the field to enhance the amount of rain by emitting ions with favourable climatic conditions. Oman appointed a local enterprise to establish the artificial rainfall project by implementing the Australian method, using the ATLANT system (Figure 1), which has proven to be statistically successful. Although ATLANT technology has only recently come to light, attempts at rainfall manipulation have been ongoing for decades. Rain enhancement technology was introduced as far back as the Second World War. The government has started to make the 12 potential stations operational, either by appointing the same company to manage them or by managing the project themselves through the Ministry of Regional Municipalities and Water Resources. Five years into the project, there had been a noticeable increase in rainfall. It rose by 18% between 2013 and 2017, a result that encouraged the state to carry the project forward to completion. The work done has considered the view of relevant literature, and data has been collected through a structured questionnaire passed to 332 participants who are considered to be stakeholders. The study hypotheses have been formulated on the basis of study propositions, and a conceptual model has been proposed to be tested in this study. It also details the key concepts in project management success and stakeholder satisfaction. The study focuses on critical success factors in project management and their impact on project management success and on stakeholder satisfaction. The work aims to identify the critical success factors contributing to project management success and to ascertain their applicability to and suitability for rainfall enhancement projects of the kind used here as a case study.
A new hail suppression project was started in Alberta in 1996. Weather Modification Inc. (WMI) of Fargo, North Dakota was awarded a five year contract by the Alberta Severe Weather Management Society of Calgary, Alberta to conduct cloud seeding to reduce urban property damage from hail, particularly for the Calgary and Red Deer areas. The operational program runs from June 15th to September15th. This project is rather unique because it is funded entirely by private insurance companies with the sole intent to mitigate the damage of property by hail storms. The seeding program is based upon the hailstorm conceptual model, seeding methods, and storm forecasting techniques of the previous long-term hail research project conducted by the Alberta Research Council from the late 1960’s through 1985. In 1996, a C-band weather radar with computer recording and communications systems and three cloud seeding aircraft were dedicated to the project. The aircraft and radar crews provided 24 hr coverage, seven days a week throughout the period. The program has been welcomed by the local communities and has rekindled much interest in cloud seeding.
the age of 86, after a brief illness.He grew up in the St. Joseph, Missouri, area, the oldest of 9 children.Paul
